Extract method refactor and passing &block

Today I've tried to refactor code by extracting some part to a method. Spuriously it didn't work.

	############################# first version
	def generate
	@volunteers.includes(
	[:user, { taggings: :tag }]
	).find_each(batch_size: 1000) do |volunteer|
	csv << VolunteerPresenter.new(volunteer).to_csv
	end
	end
	############################ second version not working
	def generate
	prefetch_volunteers do |volunteer|
	csv << VolunteerPresenter.new(volunteer).to_csv
	end
	end
	private
	def prefetch_volunteers
	@volunteers.includes(
	[:user, { taggings: :tag }]
	).find_each(batch_size: 1000)
	end

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Problem was with passing block to a method. when you do that you pass block to method not the results.
In order to fix it we need to pass a block to find_each method by using &Proc.new as an extra argument. According to this article it is a fastest method.

	def generate
	prefetch_volunteers do |volunteer|
	csv << VolunteerPresenter.new(volunteer).to_csv
	end
	end
	private
	def prefetch_volunteers
	@volunteers.includes(
	[:user, { taggings: :tag }]
	).find_each(batch_size: 1000, &Proc.new)
	end

view raw report.rb hosted with ❤ by GitHub